Pump control system



Oct. 25, 1949. c. M. BUCK 2,436,256

PUMP CONTROL SYSTEM Filed Aug. 31, 1944 7 '5 Sheets-Sheet 1 LMC,

PRESSURE cannon 66 To arm 0mm.

Oct. 25, 1949. c. M. BUCK 2,486,255

- PUMP common SYSTEM Filed Aug. 31, 1944 3 Sheets-Sheet 2 Oct. 25, 1949.c. M. BUCK 2,486,256

' PUMP CONTROL SYSTEM Filed Aug. 31, 1944 3 Sheets-Sheet 3 FIQG 3Patented Oct. 25, 1949 UNITED STATES PATENT OFFICE Claims. 1

This invention relates to a method of control and a control system forautomatically controlling in sequence and combination pressure supplypumps which may be of equal or unequal capacities.

The chief object of this invention is to supply a closed system, such asa water distribution system,

with fluid (water) under a maximum pressure and above a minimum pressureand variable according to system demand without requiring the necessityof using a pneumatic or elevated storage tank. The invention, however,ma be utilized in such systems where such tanks now are employed,thereby permitting the extension of such a system now in use and of thelatter type without discarding such tank when the system capacity has tobe increased to care for increased demands incid'ent to boom growth,such as is occurring in war industry areas.

The chief feature of the invention resides in providing a floatingcontroller for controlling a reversible electric motor driven switchcontrol, the drive being effected through a lost motion clutch wherebythis method and apparatus is successful, since the control is responsiveonly to stable conditions and temporary irregularities, such as a surgedue to an incoming pump, or cutting out of a pump does not affect thecontrol.

The present invention is further characterized by the fact that whenevera larger capacity pump is to be cut out it actually is held in operationuntil the lower capacity incoming pump (or pumps) gets up to speed sothat the system at no time is without some pressure supply andespecially when the actual change-over is being effected.

Briefly expressed, the present invention is directed to the accuratetiming of control operation, the elimination of automatic response todistribution system surges due to starting and stopping of pumps, theopening or closing of large draw offs and the like, the elimination ofuncontrolled overlap in the changing of pumps, the elimination ofhunting or rapid cutting in and out of pumps, the elimination of deadspots or periods when no service fluid is delivered, and the utilizationof low overall pressure differentials for automatic control, which is nomore than that required for the control of a single pump.

The invention herein is specifically disclosed as applied toelectrically driven pumps, but this is only for convenience and by wayof example, for it can be incorporated in a system including multiplejet steam or like turbine driven pumps,

and other powered pumps. In the second instance, the control systemdisclosed herein would be used to open and close the valves controllingthe various steam jets. Hence, herein the term switch is intended toincli'de a valve as well and such valve or valves can control the powerfluid (electric current by switches), such as compressed air, steam.mercury vapor or a hydraulic medium.

Other objects and features of the invention will be set forth more fullyhereinafter.

The full nature of the invention will be understood from theaccompanying drawing and the following description and claims:

In the drawings Fig. l is a schematic diagram of an embodiment of theinvention suflicient for an understanding of the same.

Fig. 2 is a similar diagram of a second embodiment of the invention andmore particularly the control portion thereof.

Fig. 3 is a front view of a control cabinet and certain of the controlelements therein.

Fig. 4 is a perspective view of the lost motion clutch.

It appears desirable at this time to state that the apparatus includes aselective cam-switch unit, which is reversely rotatable to the desireddegree requiredthat is in one direction to supply increasing demand andin the other direction to reduce the supply as demand decreases. Thisunit is driven by a reversible control motor through a high gearreduction train or the like and at an adjustable speed. Interposedtherebetween is the lost motion clutch.

This control motor is directly responsive to a pressure responsiveswitch in that when the pressure in the system falls to thepredetermined minimum the switch makes low pressure contact to energizethe control motor to rotate same and the selector switch in thedirection and amount suificient to cut in an additional pump. The motorthen stops, when the pressure rises.

When the new pump cuts in, if there is a surge incident thereto thatmomentaril runs the distribution system pressure above the predeterminedmaximum pressure, the pressure responsive switch then will momentarilymake high pressure contact and the motor will be reversely rotated.However, the lost motion clutch prevents rotation of the selectivecam-switch until the lost motion is taken up. By that time, however, thehigh pressure surge will have subsided so that the high pressure contactwill be broken and the pump just cut in will not be cut out.

It is by reason of the foregoing that it is possible to utilize onlythat pressure differential necessary, due to pump characteristics, for asingle pump and control any number of pumps having similarcharacteristics.

The selector disc driving motor may be any of several commerciallyavailable reversible gear head motors capable of being controlledforward, back and stop by a single pole double throw switch with aneutral position. This motor can be of the variable speed type since itis desirable to eliminate the necessity of changing gears orre-adjusting cams of the selective controller to obtain the timingrequired for satisfactory operation.

The pressure responsive switch may be one of several commerciallyavailable devices known in the art as floating controls, that is, onecapable of giving the equivalent of a single pole, double throw,switching action with an intermediate neutral position.

This pressure responsive switch may consist of a single pressure unitwith a high contact 64 and a low contact 63 and a mid or neutralposition as shown in Fig. 1; or for more convenient adjustment, a doubleunit having an independent high and low pressure operated switch. In thelatter case no contact is made when the pressure is above the setting ofthe low switch and below the setting of the high switch as the doubleunit has one common wire to the reversible drive motor M1 it is ineifect a single unit and is so considered in this description.

The time delay device, hereinafter to be referred to, can be acommerciall available instrument which essentially consists of asynchronous motor, solenoid, pawl and ratchet and switch and operates asfollows: When an external control switch is closed, this device resetsimmediately and closes a load circuit. When the external control switchis opened this time delay device opens the load circuit after anadjustable time delay interval has elapsed. The load circuit remainsopen until the external control switch is again closed when the timedelay device again resets and closes the load circuit. In view of theforegoing no further explanation or description is necessary. However,other equivalent devices may be employed in lieu of that specificallymentioned herein.

The lost motion clutch can be of any suitable type such as illustratedin Fig. 4 herein wherein a the control motor reduction drive isconnected to a shaft l carrying two adjustable fingers II and i2suitably secured thereto by collars l3 and I4 in adjusted angular spacedrelation as at l5 and I6. These may be adjusted to provide any desiredtime delay since the motor is of constant though of adjustable speedtype. Positioned between the fingers is the pin I! carried by arm l8rigid with shaft IQ of the selector cam-switch unit having adjustablymounted thereon the cams 20 with which are operatively associated thefingers 2| mounting switches such as mercury switches 22 or operating Muswitches or the like.

Shaft I9 is step-by-step operable in either direction and by thereversible control motor 23 that has a speed adjusting hand control 24,see Fig. 3. By this control and adjusting the angular spacing of arms IIand 12, the desired time delay incident to lost motion pickup can beadjusted as for example 30 seconds. This prevents selector shaftreversal more than once in every half minute and as hereinafter pointedout this eliminates hunting of the pumps, or the repeated cutting in andout of same which should occur due to substantially instantaneouspressure response of the motor pressure responsive controller per se tobe herein described.

In Fig. 1 of the drawings 25 indicates a reservoir, 26 a supply linetherefrom connected as at 21 to the intakes of three pumps 28, 29 and30. each of the desired capacity. These intakes have control valves 3|therein. The discharges 32 include check valves 33 and manual valves 34.

Each pump is motor driven and herein motors 35, 36 and 3'! drive pumps28, 29 and respectively. Each motor is connected to a supply of energy,such as supply lines 38 as at 39 through a suitable motor starter device40. Each motor starter 40 is remotely controlled by another time delaydevice indicated generally by numeral 4| and to which reference hasheretofore been made specifically. This delay device is in two sections,the switch section Nb and the time delay section 4|a.

In the former is included the contactor 42 and solenoid relay 43controlling same. Normally contactor 42 is in open circuit position andcontrols a normal voltage circuit to the motor starter 40 forautomatically closing the switch means therein for connecting the pumpmotor to the supply lines and the starting of said motor when relay 43is energized.

A switch contactor 44 controls a normal voltage circuit to the timedelay device 4ia so that when contactor 44, normally in open circuitposition. is moved to closed circuit position by another solenoid relay45, the time delay device 4|a is energized as well as solenoid 43,whereupon the motor starter is remotely controlled to effect motorstarting.

When solenoid 45 is deenergized contact 44 drops to open circuitposition and the time delay device becomes operative to mechanicallymaintain the circuit including solenoid 43 closed until the elapse ofthe predetermined interval.

At the time contact 44 drops to open circuit position another relay 45is energized to cut in another pump. However, to bring this pump up tospeed requires some time, hence determinable by the pumpcharacteristics, this time delay device holds the first pump inoperation until the second pump has been cut in and is operating. Thisoverlapping of pumps produces a momentary upsurge in the distributionsystem, which will be reflected in the pressure responsive switch andthe operation of the selector switch motor. However, due to the lostmotion clutch, such motor operation is not translated to the selectorswitch device. Hence transient effects are cancelled from the system.

Referring again to Fig. 1, it will be noted the pump header 5| not onlydischarges to the distribution system but to a branch 52 therefrom. Thisbranch includes adjusting valve 52a, gauges 53, strainer 54, controlorifice 55 and riser 56 to the pressure responsive switchbeforementioned. This line also includes relief valve 51 set for a safepressure. The relief line then wastes to a drain as at 58. A bypass 59also connects thereto and includes valve 60.

A pressure responsive element such as a sylphon or diaphragm in thehousing 6| is suitably connected to a switch member 62 and the opposedcontacts 63-64 may be adjusted for any predetermined pressurediiferential and low and high pressures. The three current lines 65666'llead from this pressure responsive switch to the control motor 68 whichis a low voltage reversible motor supplied by secondary 69 of atransformer having primary Ill connected to supply lines LI and L2.

Tapped thereto are lines H .and 12 leading to all relays 45 and 43,motor starters and time delay devices 4la as aforesaid. These lines arecontrolled by switch 13. Herein five switches I6 are connected to lineII by line 14. Line I5 connects one side of the five relays to line 12.Depending upon which switch Hi is'closed by the selector cam, theassociated relay 45 will be energized.

In Fig. 1 the fifth switch 16 is shown closed wherefore the fifth relay45 is energized to close contactor 44 of the fifth relay structure. Thisincludes two other contactors 44c and 44d. The fourth relay structureincludes contactors 44 and 44b, while the third relay structure includescontactors 44 and 44a.

Each time delay device 4lb has two lines H and I8 thereto. Contactor 44of the first relay, contactor 44 of the third relay and contactor 44d ofthe fifth relay is arranged to short circuit these lines to the firsttime delay device. Contactors 44 of the second and third relays andcontactor 44b of the fourth relay and contactor 440 of the fifth relay,each are arranged to short circuit lines '|'|'I8 of the second timedelay device 4 lb. Contactors 44 of the fourth and fifth relays arearranged to short circuit lines 11-18 of the third time delay device4lb.

By this arrangement any predetermined combination of pumps can be cut independing upon which cam actuated switch 16 is closed. Whenever it isdesired to have the minimum capacity pump operate continuously jumper I9is utilized.

As illustrated in Fig. 1, each of the mercury switches, that is the fourto the right, are shown providing a switch at the back end that isnormally closed when the switch at the front or forward end is normallyopen. Accordingly, therefore, the forward end of the left hand switch16, is operative when the jumper I9 is not included, or to have theinterlocking effect thereof, even when the jumper is included, it willbe noted that each of the four right hand switches breaks the circuitfor the preceding switch to the left when the one to the right is made.This provides an interlock of electrical character and such an interlockis also disclosed in Fig. 2 by means of a switch that is independent ofthese mercury switches.

The time delay device 4|b has been briefly described. To furtherdisclose the wiring of same it will be noted line H connects to motor 80and relay Bl. Relay 43 of device 41b connects to contact 82 to which theother side of motor 80 is connected. Switch member 83, when in closedcircuit position, contacts contact 82 and connects same by line, 84 tosupply line 12. Since the fifth relay 45 is energized all switches 83are closed.

The other side of the time delay relay 8| is connected by line 85 toline 18. As long as any relay 45 is energized the associated contactoror contactors closes or close the circuit or circuits to the relay orrelays 8|, thus closing the circuit to the relay or relays 43. At thesame time the motor 80 is energized which through the pawl and ratchet,etc., resets the time delay structure. Whenever this solenoid 45 isdeenerized all circuits controlled thereby are deenergized, except thereset controlled circuits, which are associated with contact 83, thetime delay device holding this contactor closed, even though its relayBI is deenergized. This held condition is maintained for the adjustedinterval which is that required for any pump to get up to speed. Uponelapse of this interval, the held switch 43 moves to open circuitposition No further description is believed necessary relative to Fig. 1and what is illustrated therein, or what has been described withreference there- In Figf 2, to which reference will now be had briefly,it will be noted that the pressure switch A is of dual type instead ofsingle alternative type as in Fig. 1. Herein each of the relays R havetheir common connection controlled by normally closed contactors ofsucceeding relay structures, so that any energized relay willautomatically cut out any preceding relays.

In Fig. 2 the several elements are disclosed in open circuit condition,whereas in Fig. 1 the full capacity was called for and the severalcircuits conditioned to supply the same. Herein also a manually operablelow and high pressure switch structure is interposed between thepressure switch A and control motor M and is, in effect, in multiplewith the former. Also herein the cam actuated switches include limitswitches 9| and 92 connected as illustrated. The several circuitsbetween the relays and the cam-switches also are different butfunctionally are similar.

If the three pump control is associated with pumps of 200, 400 and 800G. P. M. capacities, it is obvious that demands of 2, 4, 6, 8, 10, 12and 14 hundred gallons per minute can be satisfied therewith at thedesired average pressure, the system functioning on the predetermineddesired differential, and with the desired overlaps, and lost motionintervals.

When a plurality of pumps of like or unlike capacities are arranged forstraight sequence control, obviously each successive pump cut in merelyadds its capacity to that already applied to the distribution, so thatthere is no selective cut out required and, therefore, no time delay isnecessary, so that the time delay relay device shown may be omitted,because on decreasing demand each successively cut in pump is cut out inreverse order of cutting in. In other words, if ten pumps were used andthe demand wentto the eighth or tenth pump, the eighth or tenth pumprespectively, upon decreasing demand, would be cut out, then to decreasethe 7th or 9th pump respectively would next be cut out and so on to theminimum demand, which would be carried by pump #1.

While Fig. 1 illustrates three pumps with three individual controls anda five unit control thereof and Fig. 2 illustrates three individualcontrols for three pumps and seven individual unit controls for theaforesaid three controls, it is to be understood that the structureshown in Fig. i can be extended to a seven unit control, instead of thefive unit control actually illustrated and without any inventionfollowing the broad disclosure of Fig. 2.

While the invention has been illustrated and described in great detailin the drawings and foregoing description, the same is to be consideredas illustrative and not restrictive in character.

The several modifications described herein as well as others whichwill'readily suggest themselves to persons skilled in this art, all areconsidered to be within the broad scope of the invention, referencebeing had to the appended claims.

The invention claimed is:

1. In combination with a plurality of fluid supplying units each havingindependent power means and each connected to a common distribution lineand a control individual to each power means to cut the associated unitinto and out of the line, the combination of a single differentialpressure operable means responsive to line pressure, reversible motivemeans controlled by the single pressure operable means, meansselectively controlling the several power means individual controls, alost motion connection between the selective means and the reversiblemotive means, and a time delay device associated with each power controlfor retaining a unit to be cut out in the cut in relation until the unitto be cut into the line becomes eiIective thereon.

2. A combination as defined by claim 1 wherein the time delay device isof adjustable character for varying the time delay interval.

3. In combination with a plurality of fluid supplying units each havingindependent power means and each connected to a common distribution lineand a control individual to each power means to cut the associated unitinto and out of the line, the combination of a single differentialpressure operable means responsive to line pressure, reversible motivemeans controlled by the single pressure operable means, meansselectively controlling the several power means individual controls, alost motion connection between the selective means and the reversiblemotive means, and a time delay device associated with each power controlfor retaining a unit to be cut out in the cut in relation until the unitto be cut into the line becomes effective thereon and the difierentialpressure operable means is of adjustable character. 1

4. In a fluid distribution system, a plurality of units to supply fluidunder pressure to said system, a power source for operating each of saidunits, means operable automatically between predetermined high and lowpressure limits for energizing or deenergizing said power sources, andmeans connected with each of said power sources to continue operationthereof a predetermined time after said automatic means has operated todeenergize said power sources.

5. In a fluid distribution system, a plurality of units to supply fluidunder pressure to said system, a power source for operating each of saidunits, means operable automatically between predetermined high and lowpressure limits for energizing or deenergizing said power sources, andtime control means connected with each of said power sources andoperable to maintain a power source in operation a predetermined timeafter said source has been deenergized.

6. In a fluid distribution system, a pair of pumps to supply fluid underpressure to said system, a power source for operating each pump, meansoperable automatically between predetermined high and low pressurelimits for energizing or deenergizing said pumps, a time controllingmechanism, and means governed by said time controlling mechanism formaintaining one of said pumps in operation a predetermined time aftersaid automatic means has operated to deenergize the said one pump.

7. In a fluid distribution system, a series of independently operatedpumps to supply fluid under pressure to said system, means operatingautomatically between predetermined high and low pressure limits forenergizing said pumps luccessively, pressure operating mechanismoperable automatically to energize said pumps in sequence, and meansinterposed between said flrst mentioned pressure operating means andacid sequence control mechanism to prevent energizing of any of saidsucceeding pumps for a predetermined time period.

8. In a fluid distribution system, a series of independently operatedpumps to supply fluid under pressure to said system control, meansoperating automatically between predetermined high and low pressurelimits for energizing and deenergizing said pumps successively, pressureoperating mechanism operable automatically to energize and deenergizesaid pumps in sequence. and means interposed between said pressurecontrol meansand said sequence control mechanism to prevent energizingand deenergizing, respectively, of any of said succeeding pumps for apredetermined time period.

9. In a closed pressure distribution system the combination of aplurality of independent pressure fluid supply units, each normallyoperable between predetermined high and low pressures, a source of powerfor each unit, a control device responsive to distribution systempressure within predetermined high and low pressures therein forcontrolling the sources to effect deenergization and energizationrespectively of a unit upon rise and fall of system pressure above andbelow the last mentioned pressures, the latter being within the range ofthe flrst mentioned pressures, and time delay means operativelyassociated with the control device for delaying tor a predetermined timethe energization of an incoming unit and deenergization of an outgoingunit respectively upon fall and rise of distribution system pressure,the second mentioned pressures each being comparatively close to anaverage pressure to be maintained in said system.

10. In a pressure distribution system a plurality of independentpressure fluid supply units, an independent power supply for each unit,a distribution system high and low pressure operable single controloperatively connected to said power supplies for energizing anddeenergizing individual units upon system pressure falling and risingrespectively to the said low and high pressures of said system, and asingle time delay device interposed between said single control and thesaid power supplies to retard energization and deenergization for apredetermined time at each such operation.

CHAUNCEY M. BUCK.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 826,953 Muckle et al July 24,1906 1,009,400 Fordyce et al Nov. 21, 1911 1,050,916 Bresnahan Jan. 21,1913 1,903,763 Hott Apr. 18, 1933 1,972,812 Walley Sept. 4, 19342,029,765 Durdin Feb. 4, 1936 2,237,574 Persons Apr, 8, 1941 2,246,940Hood June 24, 1941

